The present invention relates to a method of and to an apparatus for forming a rod-like filler of fibrous material, and more particularly to improvements in methods of and apparatus for making a filler which contains several types of fibrous material, especially particles of tobacco leaves.
As used herein, the term "fibers" is intended to embrace particles of fibrous material which are used in the tobacco processing industry, especially particles of natural tobacco leaves, reconstituted tobacco, substitute tobacco (e.g., cellulose) and fibrous materials which are used in filters for tobacco smoke. Particles of tobacco leaves, reconstituted tobacco and/or substitute tobacco can consist of highly aromatic materials having a high or low nicotine content as well as of mild substances with a high or low nicotine content.
Commonly owned U.S. Pat. No. 4,009,722 to Wahle et al. discloses a method of and a machine for making cigarettes with composite fillers. The machine has a rotary wheel-shaped conveyor with peripheral pockets for accumulation of batches consisting of a first type of tobacco particles which are showered into the pockets, and the batches are thereupon assembled with a second type of tobacco in such a way that the resulting composite stream contains a file of batches which alternate with accumulations of tobacco particles of the second type. The composite stream is converted into a filler which is draped and is subdivided into cigarettes wherein the ends which are to be lighted contain "good" (aromatic) tobacco particles and the other ends (through which tobacco smoke is drawn) contain tobacco of lower quality or substitute tobacco.
Commonly owned copending patent application Ser. No. 575,169 filed Jan. 30, 1984 by Goldbach discloses a modified apparatus wherein a stream of tobacco particles is propelled into the pockets of a rotary conveyor by compressed air
A drawback of presently known batch forming apparatus is that they cannot ensure the formation of identical or substantially identical batches of tobacco particles or like fibrous materials. Thus, certain pockets receive larger quantities and other pockets receive smaller quantities of a particular type of tobacco which affects the quality of the filler and of smokers' products which are obtained as a result of draping of the filler into a web of wrapping material and subdivision of the resulting rod into sections of unit length or multiple unit length.